Intro: Insulation Displacement Screw Terminals
I am a Model Railroader and do a lot of electrical wiring. It is most important to be able to keep track of the various connections. Since it is a hobby, keeping the cost low saves money for more important things, like more trains! These Insulation Displacement Screw Terminal Strips allow connecting wires in several ways.
1) Direct one wire to another wire.
2) One wire to several branch wires.
3) One wire to ring terminals.
Step 1: Cross Section at Wires and Screw
There are many ways to connect low voltage wires. Some take trained skills like using solder. Others are easy, but the parts can get expensive quickly. Few offer an easy way to make multiple connections to a common conductor.
I was working with some PVC trim boards and thought they might make nice terminal strips. Here is a cross section through the connection between two wires connected by a hex head sheet metal screw. I did a test at 11 amps and the connection didn't show any signs of heating up. Most model railroad currents are much less.
So a wiring method that doesn't require stripping insulation off the wires. No hot soldering iron. Multiple ways to make connections. And changes are as easy as taking a screw back out.
Step 2: PVC Trim Boards
The PVC trim boards are available in various widths and are not expensive. Also the hex head sheet metal screws are available in boxes of 1000 are cheap. Making the grooves is a simple task on a table saw, or you could use a chop saw or a radial arm saw. I cut the grooves 1/4" deep and used #8 x 1/2" screws. The hex head screws used in HVAC ducts are very easy to drive with a nut driver. Also the smooth white surface is easy to mark on with a Sharpie Pen. You can even color code the grooves!
Step 3: In Use
Here is a photo from under the train table.
The left photo shows two strips. The top common terminal has one wire pushed in for the full length. The lower terminal has individual wire connections.
The right photo has one strip with the individual wires connected at left and the common connections on the right end. The common wire is wrapped in a serpentine pattern. I found this made a neater arrangement for the wires.
These terminals are 3/4" wide and only allow one screw. We found if the strip were 1.5" wide you could put in two or three screws for more wires.
Step 4: Thick and Thin Wires
While the saw cut was just right for 18GA wire, what can you do about thinner wires? I found that if you folded thin wires over until they were about the thickness of a thicker wire it would work fine.
I hope this idea is useful for your model railroad.
Please work carefully.